Kilgore answers that she doesn't, and I absolutely agree. I would go further and argue that Clinton must not repudiate welfare reform, since that repudiation might cause the election of a Republican. I think she must refrain from all criticism of the 1996 welfare reform bill. One important reason (among many others) is that by avoiding the topic during the campaign she increases the chance that she will be able to undo some of the damage.

But he is not willing to just leave it at that. He argues that welfare reform would have worked better if it were not for George Bush here

"Of course the ability to get people intro entry level jobs and into some sort of upward mobility depended heavily on what happened to the EITC, Medicaid, SNAP and many other elements of “making work pay” during a less than supportive Bush administration!"

So what happened to EITC, Medicaid, and SNAP under Bush ? Well there was a large increase in the child tax credit, which is very similar to the EITC. Medicaid and SNAP were not changed. The claim that problems with welfare reform are Bush's fault is completely unsupported by any evidence, because there is no evidence to support it. It is a red herring.

Also Kilgore doesn't discuss the 1996 welfare reform bill and SNAP (then called food stamps). The program was ruthlessly slashed by the 1996 bill. The vast bulk of the forecast reduction in social welfare spending was due to cuts to food stamps and not to the transition from AFDC to TANF. In particular one provision of the bill was that food stamps were not supposed to be provided to adults without children. This means they were supposed to get nothing at all no matter how poor they were (obviously they get neither AFDC nor TANF).

Kilgore mentions SNAP when arguing that the welfare bill was not so bad, because he has forgotten the text of the bill. I note in passing that I lived in Italy, didn't surf the web and didn't subscribe to a US newspaper at the time. I learned everything I know about the 1996 bill by reading The New Republic in 1996.

the biggest problem with the “welfare reform has failed” narrative, and with treating the Ryan budget as a logical extension of welfare reform, is that it ignores one of the main purposes of the 1996 act was to make other elements of the safety net, some work-conditional and others simply much better targeted, more central, even as they were significantly strengthened. As Elaine Kamarck explained at Ten Miles Square back in September of 2011:

[T]he intent of welfare reform was to move as many Americans as possible off the welfare rolls, which, by supporting mothers only if they weren’t working and weren’t married, created lamentable behavioral incentives. The goal was to see them then move into either the work world or the arms of other government programs that offer more targeted forms of assistance. In both respects, the law has been a success. No doubt the safety net needs shoring up. But even in these tough economic times, it is providing much more of a cushion for the kinds of families that once relied on welfare than its critics seem to realize.
In today’s WaPo, Ezra Klein takes a different tack in suggesting that welfare reform’s record is an accurate yardstick for how the Ryan budget might work out: since Ryan (and for that matter, in his own proposal, Mitt Romney) wants to turn Medicaid, food stamps and other safety-net programs into state-run block grants, it’s important to look at how states have cut TANF to see how they might handle these other programs.

Ezra’s right about that, but like Paul Ryan, he’s mixing apples and oranges: TANF costs and caseloads were intended to go down in no small part because the other safety net programs, along with the extremely important earned income tax credit (EITC) were intended to pick up the slack.

In 2015 he correctly wrote

is Clinton’s record on “poverty and the safety net” entirely reducible to the 1996 welfare law? Definitely not; you could make a pretty good case that Clinton’s whole strategy was to shift the emphasis from wildly unpopular, inadequate and state-controlled cash assistance to other, federally controlled income support mechanisms, including the EITC that had already been greatly increased long before the third welfare bill hit his desk.

So the 1993 EITC expansion has changed from being one of the "main purposes of the 1996 act" to something which happened long before.

In 2012 Kilgore was writing based on an incorrect recollection of the events. He accused Klein of mixing apples and oranges because he Kilgore and not Klein insisted on mixing apples and oranges and assuming that 1993=1996.

Kilgore should update his 2012 post to note his error. He should also try to revise the argument he made in 2012 to see if it can still stand without the support of the false claim of fact. I think it is very clear that it doesn't and that recognition of the undeniable facts of history makes it impossible for Kilgore to defend his 2012 conclusions. Note the absense of any argument that the 1996 reform was an improvent in the 2015 post which mostly argues that discussing it is bad politics (I agree) and that it is no big deal (I passionately disagree).

I also think that Kilgore owes Exra Klein and Jason DeParle apologies and that he should make those apologies both in person and publicly.

But mostly I think he really has to stop mixing discussion of politics and policy. He can discuss political strategy without discussing the effects of hypothetical policy reforms (especially those which are politically impossible). But he just can't resist. He also has trouble refraining from linking to Elaine Kamarck who has trouble sticking to policy analysis.

I think it has finally become very clear to Kilgore that the 1996 welfare reform bill was bad policy. He clearly stongly believes that it is a topic which Democrats should avoid (so does Bernie Sanders). But he can't resist attempting some argument that, back in 1996, the lefties who disagreed with him weren't entirely right. He can't make a counter argument (he didn't try in 2015) but he can't either force himself to concede (which is painful) or discuss political strategy only without trying to hint that we weren't right about policy back in 1996.